ISOLATION OF ALPHA-TOXIN, THETA-TOXIN AND KAPPA-TOXIN MUTANTS OF CLOSTRIDIUM-PERFRINGENS BY TN916 MUTAGENESIS

Clostridium perfringens is the causative agent of clostridial myonecro sis or gas gangrene and mediates infection and disease by producing nu merous extracellular toxins, including alpha-toxin, theta-toxin and ka ppa-toxin. Tn916-mutagenesis was used to isolate mutants defective in their ability to produce either alpha-toxin or theta-toxin. Nine indep endently derived mutants were isolated. In four of these mutants Tn916 had inserted at sites located 193 bp or 198 bp upstream of the theta- toxin structural gene, pfoA. Four mutants contained large deletions, t hree in regions which encompassed the theta-toxin structural and regul atory genes pfoA and pfoR, respectively, and the K-toxin structural ge ne, colA, and one in a region encompassing the a-toxin structural gene , pie. These mutants should prove to be invaluable for further genetic studies aimed at determining the role of these toxins in virulence. ( C) 1997 Academic Press Limited.